The invention is directed to an electrical relay having a housing that comprises a floor side for putting in place on a printed circuit board and from which terminal leads that are provided with terminal lugs for contacting on the printed circuit board emerge.
In traditional relays, the terminal leads usually emerge from the floor side of the housing and the terminal lugs they form are soldered into bores of the printed circuit board proceeding from the bottom side of the printed circuit board. Recently, what is referred to as the surface mounting technique (SMT) has become more and more common, especially for small components, whereby the components have flat terminal lugs lying on the printed circuit board and are soldered by introducing heat from the upper side. A one-time, albeit brief-duration, but nonetheless high thermal load, this arises for the component parts. In order to be able to mount and solder relays together with other components in a uniform work cycle, the terminal leads of these relays that emerge at the floor side or from the sidewalls in the floor-proximate region are also bent over to form flat contacts parallel to the floor side (EP 0 171 808 B1). What this means for the relays is that materials and technologies must satisfy the most stringent demands, this being expressed in high manufacturing costs. Among other things, there is thus a risk that a de-adjustment will occur in the inside due to the differences in the thermal expansion of the materials; this is especially caused by the proximity of the solder locations to the housing lead-throughs in the lower housing region. Due to the free inside volume that is necessarily present in relays, the great heating also effects a great increase in the pressure of the air in the inside of the housing. This can lead to a loss of tightness.
In order to avoid the disadvantages occurring during soldering, it has likewise already been proposed to design the terminal leads of relays as press-in stems, so that the relay can be put in place on the printed circuit board after the soldering and can be contacted with a press-in technique (DE 34 30 589 C2). Since the press-in stems in previous proposals and their press-in shoulders are applied to the terminal leads more or less directly where these emerge from the lower region of the relay housing, there is a risk that the press-in forces will be transmitted directly onto the sealed lead-through region and into the interior of the relay, where they can have a negative effect on the sealing and on the adjustment values of the relay.